Optical discs provide a reliable long term storage medium available for digital information. In order to automate archived optical disc storage in a cost effective manner, optical discs are shelved for occasional automated retrieval. It is desired to minimize the amount of space that the optical discs themselves occupy so as to maximize optical disc storage density. As such, optical discs are stacked as closely together as possible. A problem with closely stacking optical discs is the subsequent process of accessing a specific optical disc within a tightly spaced optical disc stack. One technique of accessing a specific optical disc within an optical disc stack is to use a robotic gripper. The specific optical disc is accessed by moving the robotic gripper a determined distance within the optical disc stack based on an anticipated average thickness of each optical disc. However, variances in manufacturing tolerances for optical disc thicknesses results in inaccurate determination of a specific optical disc position within an optical disc stack.